Systems and methods for securing access to resources

ABSTRACT

In some embodiments, a resource security system may determine an access request outcome (e.g., accept, reject, or review) for an access request based on access rules. The resource security system may generate and select the access rules to be used for using stability information. For instance, the resource security system may select a training set from the received access requests, e.g., including recently received access requests, and generate a plurality of potential access rules based on the training set. The resource security system may determine and compare the detection performance and the stability performance of the potential access rules. The resource security system may select the best performing potential access rules to be used in operation for determining the outcome of access requests.

CROSS-REFERENCE TO RELATED APPLICATIONS

This present application is a continuation of U.S. application Ser. No.16/134,875, filed Sep. 18, 2018, which is a continuation application ofU.S. application Ser. No. 15/812,334, filed Nov. 14, 2017, now U.S. Pat.No. 10,110,621, issued Oct. 23, 2018, which is a continuation of U.S.application Ser. No. 15/352,491, filed Nov. 15, 2016, now U.S. Pat. No.9,853,993, issued Dec. 26, 2017, the entire contents of which are hereinincorporated by reference for all purposes.

BACKGROUND

An unauthorized user may fraudulently request access to a resource usingthe authorization information of an authorized user. To preventunauthorized access, a resource security system may implement accessrules to reject access requests having certain parameters that areindicative of fraud. However, in response to being denied access, theunauthorized user may change their method for making fraudulent accessrequests, thereby changing the parameters, in order to avoid rejectionby the access rules. In addition, authorized users may also change theirmethods for making legitimate access requests over time. Consequently,the performance of the access rules may degrade over time, increasinglydenying access to authorized users or increasingly granting access tounauthorized users. Accordingly, there is a need for improved systemsand methods for securing access to resources.

BRIEF SUMMARY

In some embodiments, a resource security system may determine an accessrequest outcome (e.g., accept, reject, or review) for an access requestbased on access rules. The resource security system may generate andselect the access rules based on their performance and their stabilityover time. For instance, the resource security system may select atraining subset from the set of received access requests, e.g.,including recently received access requests, and generate a plurality ofpotential access rules based on the training set. The resource securitysystem may determine and compare the performance and the stability ofthe potential access rules. The resource security system may select thebest performing and most stable potential access rules to be used fordetermining the outcome of an access request.

In some embodiments, the resource security system may determine andtrack the triggering percentage and the predictive percentage for eachpotential access rule over time. The resource security system may thendetermine the stability of the triggering percentage and the predictivepercentage for each potential access rule. In some embodiments, theresource security system may determine the predictive percentage and itsstability based on an expected delay in the reporting of fraudulentaccess. Accordingly, the access rule generation system may select accessrules that have high fraud predictive percentages and that are stableover time, thereby reducing fraudulent access and also reducing falsepositives.

Other embodiments are directed to systems, portable consumer devices,and computer readable media associated with methods described herein.

A better understanding of the nature and advantages of embodiments ofthe present invention may be gained with reference to the followingdetailed description and the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a resource security system for authorizing access toresources, in accordance with some embodiments

FIG. 2 shows a functional block diagram of an access server fordetermining an access request outcome, in accordance with someembodiments.

FIG. 3 shows a functional block diagram of an access rule generationsystem for generating and selecting access rules, in accordance withsome embodiments.

FIG. 4 shows an exemplary graph of triggering percentages for two accessrules over time, in accordance with some embodiments.

FIG. 5 shows an exemplary graph of the observed predictive percentagesfor two access rules over time, in accordance with some embodiments.

FIG. 6 shows a functional block diagram of an access rule generationsystem for generating and selecting access rules that are stable overtime, in accordance with some embodiments.

FIG. 7 shows an exemplary graph of the time delay in the reporting offraudulent access requests, in accordance with some embodiments.

FIG. 8 shows a graph of observed predictive percentages and compensatedpredictive percentages for an access rule over time, in accordance withsome embodiments.

FIG. 9 shows a functional block diagram of an access rule generationsystem for generating and selecting access rules based onreporting-delay information, in accordance with some embodiments.

FIG. 10 shows a flowchart of a method for generating and selectingstable access rules, in accordance with some embodiments.

FIG. 11 shows a flowchart of a method for generating and selectingaccess rules based on compensated validity information, in accordancewith some embodiments.

FIG. 12 shows a functional block diagram of components of an exemplarycomputer system including an access rule generation system and an accessserver, in accordance with some embodiments.

TERMS

Prior to discussing embodiments of the invention, description of someterms may be helpful in understanding embodiments of the invention.

The term “resource” generally refers to any asset that may be used orconsumed. For example, the resource may be an electronic resource (e.g.,stored data, received data, a computer account, a network-based account,an email inbox), a physical resource (e.g., a tangible object, abuilding, a safe, or a physical location), or other electroniccommunications between computers (e.g., a communication signalcorresponding to an account for performing a transaction).

The term “access request” generally refers to a request to access aresource. The access request may be received from a requesting computer,a user device, or a resource computer, for example. The access requestmay include authorization information, such as a user name, accountnumber, or password. The access request may also include and accessrequest parameters, such as an access request identifier, a resourceidentifier, a timestamp, a date, a device or computer identifier, ageo-location, or any other suitable information.

The term “access rule” may include any procedure or definition used todetermine an access rule outcome for an access request based on certaincriteria. In some embodiments, the rule may comprise one or more ruleconditions and an associated rule outcome. A “rule condition” mayspecify a logical expression describing the circumstances under whichthe outcome is determined for the rule. A condition of the access rulemay be involved by an access request parameter based on the parameterhaving a specific parameter value, based on the parameter value beingwithin a certain range, based on the parameter value being above orbelow a threshold, or any combination thereof.

An “access rule outcome” of an access rule may represent an outcomedetermined by that rule based on one or more conditions of the rule andthe parameters of the access request. For example, an access rule mayprovide an access rule outcome of either “reject,” “accept,” or“review,” when its conditions are involved by an access request.

The term “access request outcome” may include any determination ofwhether to grant access to the resource. The access request outcomes mayinclude “accept,” “reject,” or “review.” In some embodiments, an accessrequest outcome for an access request may be “reject” if any of theaccess rules have an access rule outcome of “reject.” In someembodiments, an access request outcome for an access request may be“accept” if any of the access rules have an access rule outcome of“accept,” regardless of any outcome being “reject.” An access requestoutcome of “accept” may cause the access request to be granted. Anaccess request outcome of “reject” may cause the access request to bedenied. The “review” outcome may initiate a review process for theaccess request. In various embodiments, other outcomes or other meaningsof these outcomes may be used.

The term “triggering percentage” is a metric that describes thepercentage of access requests received over a certain period of timethat satisfy (e.g., involve or meet) one or more conditions of a certainaccess rule. That is, the access rule is “triggered” by an accessrequest that involves the conditions of the access rule. In one example,an access rule may be triggered by 100 access requests out of 1,000,000access requests received in one month. That is, the “triggeringfrequency” of the access rule is 100 per month. Accordingly, thetriggering percentage of the access rule over that one month is 0.01%(e.g., 100÷1,000,000).

The term “predictive percentage” refers to the percentage of accessrequests triggering an access rule that are predicted to be fraudulent.The fraud predictive percentage may be determined based on reports offraudulent (e.g., invalid of unauthorized) access requests. For example,if an access rule is triggered by 100 access requests within a certaintime period and 90 of those access requests are reported to befraudulent, then the predictive percentage of the access rule for thattime period may be determined to be 90% (e.g., 90÷100).

The term “reporting” generally refers to a process for identifyingwhether an access request was fraudulent or legitimate. Reporting mayinvolve a user of a resource reporting unauthorized use to the owner oroperator of the resource. For example, an owner of a payment account mayinitiate a charge-back for a fraudulent transaction on their account. Inanother example, a user of an email account may report a certain emailas being “junk” or “spam” mail. In some situations, an authorized userof a resource may report a denial of access to the resource. Forexample, a user may report that a legitimate transaction was denied, orthe user may report that an email is “not-spam.” Such reporting may beused to determine validity information (e.g., valid/legitimate orinvalid/fraudulent) for the corresponding access request.

The term “server computer” may include a powerful computer or cluster ofcomputers. For example, the server computer can be a large mainframe, aminicomputer cluster, or a group of computers functioning as a unit. Inone example, the server computer may be a database server coupled to aweb server. The server computer may be coupled to a database and mayinclude any hardware, software, other logic, or combination of thepreceding for servicing the requests from one or more other computers.The term “computer system” may generally refer to a system including oneor more server computers coupled to one or more databases.

As used herein, the term “providing” may include sending, transmitting,making available on a web page, for downloading, through an application,displaying or rendering, or any other suitable method. In variousembodiments of the invention, rule profiles, rule outcome frequencies,and rule outcome disposition frequencies may be provided in any suitablemanner.

DETAILED DESCRIPTION

A resource security system may be used to grant or deny access toresources. In addition, the resource security system may implementaccess rules to reject access requests having parameters indicative offraud. The resource security system may evaluate the performance of theaccess rules based on reports of fraudulent access. The resourcesecurity system may also compensate validity information for the accessrequests based on an expected reporting delay. Then, the resourcesecurity system may determine the stability of the rules performanceover time and select stable rules to be implemented. Periodically, theresource security system may change or update the access rules based ontheir performance.

I. Resource Security System

A resource security system may receive requests to access a resource.The resource security system may include an access server fordetermining an outcome for the access request based on access rules. Theresource security system may also include an access rule generationsystem for generating and selecting the access rules. The resourcesecurity system is described in further detail below.

A. Resource Security System for Securing Access to a Resource

FIG. 1 shows a resource security system 100 for authorizing access toresources, in accordance with some embodiments. The resource securitysystem 100 may be used to provide authorized users access to a resourcewhile denying access to unauthorized users. In addition, the resourcesecurity system 100 may be used to deny fraudulent access requests thatappear to be legitimate access requests of authorized users. Theresource security system 100 may implement access rules to identifyfraudulent access requests based on parameters of the access request.The access rules may be selected based on their performance and theirstability over time.

The resource security system 100 includes a resource computer 110. Theresource computer 110 may control access to a physical resource 118,such as a building or a lockbox, or an electronic resource 116, such asa local computer account, digital files or documents, a networkdatabase, an email inbox, a payment account, or a website login. In someembodiments, the resource computer may be a webserver, an email server,or a server of an account issuer. The resource computer 110 may receivean access request from a user 140 via a user device 150 (e.g., acomputer or a mobile phone) of the user 140. The resource computer 110may also receive the access request from the user 140 via a requestcomputer 170 coupled with an access device 160 (e.g., a keypad or aterminal). In some embodiments, the request computer 170 may be aservice provider that is different from the resource provider.

The access device 160 and the user device 150 may include a user inputinterface such as a keypad, a keyboard, a finger print reader, a retinascanner, any other type of biometric reader, a magnetic stripe reader, achip card reader, a radio frequency identification reader, or a wirelessor contactless communication interface, for example. The user 140 mayinput authorization information into the access device 160 or the userdevice 150 to access the resource. The authorization information mayinclude one or more of a user name, an account number, a token, apassword, a personal identification number, a signature, and a digitalcertificate, for example. In response to receiving authorizationinformation input by the user 140, the user device 150 or the requestcomputer 170 may send an access request to the resource computer 110along with one or more parameters of the access request. The accessrequest may include the authorization information provided by the user140.

In one example, the user 140 may enter one or more of an account number,a personal identification number, and password into the access device160, to request access to a physical resource (e.g., to open a lockedsecurity door in order to access a building or a lockbox) and therequest computer 170 may generate and send an access request to theresource computer 110 to request access to the resource. In anotherexample, the user 140 may operate the user device 150 to request thatthe resource computer 110 provide access to the electronic resource 116(e.g., a website or a file) that is hosted by the resource computer 110.In another example, the user device 150 may send an access request(e.g., an email) to the resource computer 110 (e.g., an email server) inorder to provide data to the electronic resource 116 (e.g., deliver theemail to an inbox). In another example, the user 140 may provide anaccount number and/or a personal identification number to an accessdevice 160 in order to request access to a resource (e.g., a paymentaccount) for conducting a transaction.

In some embodiments, the resource computer 110 may verify theauthorization information of the access request based on informationstored at the request computer 170. In other embodiments, the requestcomputer 170 may verify the authorization information of the accessrequest based on information stored at the resource computer 110.

The resource computer 110 may receive the request substantially inreal-time (e.g., account for delays computer processing and electroniccommunication). Once the access request is received, the resourcecomputer 110 may determine parameters of the access request. In someembodiments, the parameters may be provided by the user device 150 orthe request computer 170. For example, the parameters may include one ormore of: a time that the access request was received, a day of the weekthat the access request was received, the source-location of the accessrequest, the amount of resources requested, an identifier of theresource being request, an identifier of the user 140, the access device160, the user device 150, the request computer 170, a location of theuser 140, the access device 160, the user device 150, the requestcomputer 170, an indication of when, where, or how the access request isreceived by the resource computer 110, an indication of when, where, orhow the access request is sent by the user 140 or the user device 150,an indication of the requested use of the electronic resource 116 or thephysical resource 118, and an indication of the type, status, amount, orform of the resource being requested. In other embodiments, the requestcomputer 170 or the access server 120 may determine the parameters ofthe access request.

While the access request may include proper authentication information,the resource computer may send the parameters of the access request tothe access server 120 in order to determine whether the access requestis fraudulent. The access server 120 may store one or more access rules122 for identifying a fraudulent access request. Each of the accessrules 122 may include one or more conditions corresponding to one ormore parameters of the access request. The access server 120 maydetermine an access request outcome indicating whether the accessrequest should be accepted (e.g., access to the resource granted),rejected (e.g., access to the resource denied), or reviewed by comparingthe access rules 122 to the parameters of the access request as furtherdescribed below. In some embodiments, instead of determining an accessrequest outcome, the access server 120 may determine an evaluation scorebased on outcomes of the access rules. The evaluation score may indicatethe risk or likelihood of the access require being fraudulent. If theevaluation score indicates that the access request is likely to befraudulent, then the access server 120 may reject the access request.

The access server 120 may send the indication of the access requestoutcome to the resource computer 110 (e.g., accept, reject, or review).In some embodiments, the access server 120 may send the evaluation scoreto the resource computer 110 instead. The resource computer 110 may thengrant or deny access to the resource based on the indication of theaccess request outcome or based on the evaluation score. The resourcecomputer 110 may also initiate a review process for the access request.

In some embodiments, the access server 120 may be remotely accessed by auser. The access server 120 may store data in a secure environment andimplement user privileges and user role management for accessingdifferent types of stored data. For example, user privileges may be setto enable users to perform one or more of the following operations: viewlogs of received access request, view logs of access request outcomes,enable or disable the execution of the access rules 122, update ormodify the access rules 122, change certain access request outcomes.Different privileges may be set for different users.

The resource computer 110 may store access request information for eachaccess requests that it receives. The access request information mayinclude the parameters of each of the access requests. The accessrequest information may also include an indication of the access requestoutcome for the access request. The resource computer 110 may also storevalidity information corresponding to each access request. The validityinformation for an access request may be initially based on its accessrequest outcome. The validity information may be updated based onwhether the access request is reported to be fraudulent. In someembodiments, the access server 120 or the request computer 170 may storethe access request information and the validity information.

The access rules 122 implemented by the access server 120 may begenerated by an access rule generation system 130. The access rulegeneration system 130 may generate candidate access rules 134 for theaccess server 120 based on the access request information and thevalidity information. The access rule generation system 130 may receivethe access request information and the validity informationcorresponding to the access request information from the resourcecomputer 110 or the access server 120. The access rules 122 implementedby the access server 120 may include some or all of the candidate accessrules 134.

The access rule generation system 130 may periodically re-generate thecandidate access rules 134 based on new or updated access requestinformation and new or updated validity information. As such, thecandidate access rules 134 may be based on the most recent patterns offraudulent resource use and the most recent patterns of legitimateresource use. The generation and selection of candidate access rules isfurther described below.

B. Access Server for Determining an Access Request Outcome

FIG. 2 shows a functional block diagram of an access server 200 fordetermining an access request outcome, in accordance with someembodiments. A resource computer may provide the parameters of an accessrequest to the access server 200 to determine whether the access requestis fraudulent. The access server 200 may implement access rules 222 todetermine the access request outcome or an evaluation score based on theparameters of the access request. The access server may load the accessrules 222 into a system memory of the access server. The access server200 may then provide the outcome or an evaluation score back to theresource computer, which may grant or deny access to the resourceaccordingly.

The access server 200 may operate similar to the access server 120 ofFIG. 1 described above. The access server 200 may be used in a resourceaccess system similar to the resource access system 100 of FIG. 1described above. The access server 200 may store one or more accessrules 222. The access rules 222 may be generated by and received from anaccess rule generation system. The one or more access rules 222 may beloaded into a memory of the access server 200 to be used in determiningan access request outcome.

At 201, the access server 200 may obtain the access request parametersfor a certain access request. The access request parameters may bereceived from a resource computer or from a request computer. The accessrequest and/or the access request parameters may be received by fromaccess server 200 from the resource computer over a network inreal-time. The parameters may include, for example, one or more of thetime that the access request was received, the day of the week that theaccess request was received, the source-location of the access request,the amount of resources requested, an identifier of the resource beingrequest, an identifier of the user 140, the access device 160, the userdevice 150, the request computer 170, a location of the user 140, theaccess device 160, the user device 150, the request computer 170, anindication of when, where, or how the access request is received by theresource computer 110, an indication of when, where, or how the accessrequest is sent by the user 140 or the user device 150, an indication ofthe requested use of the electronic resource 116 or the physicalresource 118, and an indication of the type, status, amount, or form ofthe resource being requested. may determine the parameters of the accessrequest. In some embodiments, the user 140, the user device 150, theaccess device 160, or the request computer 170 may provide one or moreparameters of the access request.

In response to obtaining the access request parameters, the accessserver 200 may access the system memory of the access server 200 toobtain the access rules. At 202, the access server 200 may determine anaccess rule outcome for each access rule 222. Each access rules 222includes certain conditions that may be satisfied by the parameters ofthe access request. The access server 200 may compare the parameters ofthe access request to the conditions of each access rule 222 todetermine whether an access rule 222 is triggered by the access request.Each access rule 222 may have an associated access rule outcome. In someembodiments the access rule outcome may indicate accept, reject, orreview. In some embodiments the access rule outcome may be an evaluationscore.

In one example of determining an access rule outcome, an access requestmay be for a website account login and the parameters of the accessrequest may include a “source location” indicating the geographiclocation of the user or device that is requesting access and an“authorized user location” indicating the geographic location of theauthorized user of the website account. In this example, a certainaccess rule may have conditions that are satisfied (e.g., triggered)when the “source location” does not match the “authorized userlocation,” and that access rule may have an outcome of “reject.”Accordingly, an access request coming from a geographic location thatdoes not match the geographic location of the authorized user may berejected.

In another example of determining an access rule outcome, an accessrequest may be for a payment transaction and the parameters of theaccess request may include the “transaction amount” and the “shippingcountry” for shipping goods purchased in the transaction. In thisexample, a certain access rule may have conditions that are satisfiedwhen the “transaction amount” is over $1,000 and when the “shippingcountry” is a country having high reporting of fraud. This access rulemay have an access request outcome of “reject.” Accordingly, a accessrequest for a transaction to ship goods amounting to over $1,000 to acertain country may be rejected.

In another example of determining an access rule outcome, an accessrequest may be for delivering an email message to an inbox and theparameters of the access request may include one or more alphanumerickeywords from then email message and a “source IP address” of the emailmessage. In this example, a certain access rule may have conditions thatare satisfied when one or more of the keyword parameters matches one ormore stored key words indicating “spam” email. That access rule may alsohave conditions that are satisfied when the IP address falls within acertain range of IP addresses reported to be spam. Accordingly, a spamemail message may not be delivered to an inbox when it contains certainkeywords and it is sent from certain IP addresses.

At 203, after determining the access rule outcome for each of the accessrules 222, the access server 200 may determine an access requestoutcome. The access request outcome may be accept, reject, or review.For example, the access server 200 may determine an access requestoutcome of “accept” if any of the access rule outcomes are “accept.” Inanother example, the access server 200 may determine an access requestoutcome of “reject” if one or more of the access rule outcomes are“reject” and none of the access rule outcomes are “accept.” In anotherexample, the access server 200 may determine an access request outcomeof “review” if one or more of the access rule outcomes are “reject” andone or more of the access rule outcomes are “accept.” In otherembodiments, the access server 200 may determine an evaluation scorebased on the access rule outcomes. The access server 200 may send theaccess request outcome or the evaluation score to the resource computer.

After determining the access request outcome at 203, the access server200 may provide an indication of the access request outcome back to thecomputer that sent the access request or access request parameters tothe access server 200 (e.g., the resource computer or the requestcomputer). The resource computer may receive the indication of theaccess request outcome and provide access to the resource based on theaccess request outcome.

In some embodiments, when the access rule outcome is “reject,” theaccess server 200 may decide to evaluate the performance of thetriggered access rule by changing the access rule outcome to “accept”instead. By accepting the access request, the performance of thetriggered access rule may be evaluated since the access request may bereported as fraudulent. Therefore, if fraudulent access is not reportedfor the triggered access rule, then the triggering of the access rulewas a false positive.

The access server 200 may determine whether to evaluate the access rulebased on different criteria, such as the number of access requestsreceived overall, the number of access requests received that triggeredthis access rule, the amount of time since the last evaluation, theamount of time since the this access rule was evaluated, or based on arandom number generator.

Evaluating the access rules 222 currently implemented by the accessserver 200 may be advantageous since the access rules 222 may have beengenerated based on patterns of fraudulent and legitimate access requeststhat have changed over time. Therefore, by accepting the access requestinstead of rejecting it, it is possible determine the performance of thecurrently implemented access rules 222 based on reports received for theaccess request triggering the access rules 222. That is, the percentageof true positives and the percentage of false positives generated byeach access rule 222 may be determined based on validity informationcorresponding to the reports.

C. System for Generating and Selecting Access Rules

FIG. 3 shows a functional block diagram of an access rule generationsystem 300 for generating and selecting access rules, in accordance withsome embodiments. The access rule generation system 300 may generate thecandidate access rules 324 based on previously received access requestsand corresponding validity information. The access rule generationsystem 300 may then provide the candidate access rules 324 to an accessserver to be used for determine an access request outcome. The accessrule generation system 300 may operate similar to the access rulegeneration system 130 of FIG. 1. The access rule generation system 300may be implemented in a resource access system similar to the resourceaccess system 100 of FIG. 1 described above.

The access rule generation system 300 may store access requestinformation 310 and corresponding validity information 320 for use ingenerating candidate access rules 324. The access request information310 and the validity information 320 may be received from a resourcecomputer, a request computer, or an access server. At 301, the accessrule generation system 300 may select a subset of access requests fromthe stored access request information 310 to obtain a training set 330of access requests for use in generating the candidate access rules 324.The access rule generation system 300 may select access requests to beincluded in the training set 330 based on the time and date when theaccess request was received. For example, the access rule generationsystem 300 may select access requests that occurred within a time periodbetween six months ago and eighteen months ago. In some embodiments, theaccess rule generation system 300 may not select access requestsoccurring within the past six months because there may be a delay of upto six months in reporting fraudulent access requests. In otherembodiments, the access rule generation system 300 may also select othertime periods.

The access rule generation system 300 may also select the training setsuch that it includes both recent access requests (e.g., those occurringwithin the past eighteen months) and historical access requests (e.g.,those occurring more than eighteen months ago). As such, the trainingset may contain access requests that are representative of both recentpatterns of fraud and older patterns of fraud. Accordingly, thecandidate access rules generated based on this training set may detectfraud made according to both new and old methods or patterns.

At 302, the access rule generation system 300 may generate a pluralityof potential access rules 340 based on the training set 330 of accessrequests. In some embodiments, the access rule generation system 300 maygenerate the potential access rules based on a decision tree. Forinstance, each node of the decision tree may represent a condition of anaccess rule parameter and branches of the decision tree may representpotential access rules 340. In some embodiments, each access rule of thepotential access rules 340 may have conditions that are mutuallyexclusive to the conditions of the other potential access rules. Thatis, an access request of the training set 330 may only satisfy (e.g.,trigger) the conditions of a single access rule of the potential accessrules 340.

In some embodiments, instead of selecting all of the possible rules thatmay be generated using a training set 330, the access rule generationsystem 300 may generate the potential access rules 340 by selectingbranches of the decision tree that are known to have higher fraudpredictive percentages based on historic information. This method maygenerate fewer potential access rules 340, thereby reducing the amountof computing and storage resources used in generating and evaluatingpotential access rules 340 for candidate access rule selection.

After generating the plurality of potential access rules 340, the accessrule generation system 300 may determine, at 303, the performance ofeach of the potential access rule 340. The performance of a potentialaccess rule may be based on the validity information 320 correspondingto the access requests of the training set 330 that satisfy theconditions of the potential access rule. For example, access rulegeneration system 300 may determine the performance of a potentialaccess rule 340 based on the percentage of access requests in thetraining set 330 triggering the potential access rule which are reportedto be fraudulent (e.g., the predictive percentage). As such, theperformance of an access rule is aggregating across all of thetriggering access requests in the training set.

At 304, the access rule generation system 300 may select a set ofcandidate access rules 334 from the potential access rules 340 bycomparing the performances of the potential access rues 340. Forexample, the access rule generation system 300 may select the twentybest performing potential access rules to comprise the set of candidateaccess rules 334. In some embodiments, the access rule generation system300 may also select a different number of candidate access rules 334.The candidate access rules 334 may be provided to the operator of theresource and some or all of the candidate access rules 334 made be usedas the access rules implemented by an access server.

II. Stability Analysis of Access Rules Over Time

The selection of candidate access rules may be based on the stability ofa potential access rule in addition to its performance. While theperformance of an access rule may be based on the aggregated predictivepercentage across all access requests in the training set, the stabilityof an access rule may account for trends or variations in performanceover time. As such, selecting candidate access rules based on theirstability may provide more consistency in the access request outcomes.

A. Stability of Triggering Percentage of an Access Rule Over Time

The triggering percentage of an access rule may be determined based onthe percentage of access requests in the training set that that involve(i.e., satisfy) one or more conditions of that access rule. In general,when the triggering percentage of an access rule increases, the amountof false positives generated by the access rule also increases. In orderto reduce false positives, an access rule generation system may selectaccess rules having higher triggering stability.

FIG. 4 shows an exemplary graph 400 of triggering percentages for twoaccess rules over time, in accordance with some embodiments. The graph400 shows the triggering percentage of a first rule, Rule A (indicatedby a solid line), according to the date that the access request wasreceived. The graph 400 also shows the triggering percentage of a secondrule, Rule B (indicated by a dashed line), according to the date thatthe access request was received.

In general, when the triggering percentage increases, the amount offalse positives also increases, and thus, the predictive percentagedecreases. For example, fraudsters may realize that their fraudulentaccess requests are being rejected and they may change their manner ofcommitting fraud to avoid being rejected by the access rules. However,the behavior of legitimate users may not change as much over time. Assuch, the false positive percentage for an access rule may increase overtime as fraudsters stop making access requests according to the patternsbeing rejected by that access rule. Therefore, it is advantageous totrack the stability of the triggering percentage over time since thetriggering percentage can be directly determined from the receivedaccess requests. That is, the triggering percentage is not dependentupon reporting, whereas the predictive percentage is.

As shown in the graph 400, Rule A may have had a triggering percentagethat is over 0.10% at the time when testing of the access rules began.Between the time that testing began and 6 months ago, the triggeringpercentage of Rule A may have dropped below 0.05% for a period of timeand then risen back up to over 0.10% later. Then, the triggeringpercentage of Rule A may have risen to over 0.15% by today, when rulegeneration and selection is being performed. Thus, the triggeringpercentage of Rule A has fluctuated from under 0.05% to over 0.15% sincetesting began.

As shown in the graph 400, Rule B may have had a triggering percentagethat was greater than 0.05% but less than 0.10% since the time whentesting began until today. As such, the triggering percentage of Rule Bhas less variation over time compared to the triggering percentage ofRule A. The variation of the triggering percentages for Rule A mayindicate that Rule A is more sensitive to changes in user behavior thanRule B, which may make Rule A less accurate during certain periods oftime, and thus, less consistent compared to Rule B.

The rule generation computer may determine a triggering stability ratingfor an access rule based on the variation of the triggering percentagesover time. For example, the rule generation computer may segment theaccess requests of the training set into time-based subsets based on thetiming of when the access requests were received. Each segment maycorrespond to a certain time-period (e.g., time window). The rulegeneration computer may then determine the triggering percentages foreach of the time-based segments and compute the variation of thetriggering percentages. In some embodiments, the access request may besegmented week-by-week or day-by-day. In other embodiments, the accessrequests may be segmented using a sliding window such that thetriggering percentages are calculated each day over a one week window.

Based on the variation of the triggering percentages of the segments,the rule generation computer may determine that Rule B has a highertriggering stability rating compared to Rule A, since the triggeringpercentage of Rule B varies less over time. The access rule generationsystem may use the triggering stability ratings of the potential accessrules to select candidate access rules that are stable, and thus, moreaccurate and more consistent over time.

B. Stability of the Predictive Percentage of an Access Rule Over Time

The predictive percentage may be determined based on the percentage ofaccess requests triggering an access rule that are reported tofraudulent. Certain access rules may have a high predictive percentagein the aggregate but they may be sensitive to changes in access requestbehavior during certain periods of time. In order to reduce falsepositives, an access rule generating system may determine the predictivepercentage of an access rule over time and select access rules havinghigher detection stability.

FIG. 5 shows an exemplary graph 500 of the observed predictivepercentages for two access rules over time, in accordance with someembodiments. The graph 500 shows the percentage of access requeststriggering a first rule, Rule A (indicated by a solid line), that arefraudulent according to the date that the access requests were received(e.g., an observed predictive percentage). The graph 500 also shows thepercentage of access requests triggering a second rule, Rule B(indicated by a dashed line), that are fraudulent according to the datethat the access requests were received. The observed predictivepercentage may be based on the validity information corresponding to theaccess requests.

As shown in the graph 500, Rule A may have an observed predictivepercentage that varies from over 90% to under 40%, with severalvariations between 50% and 70% over the time from when testing began to6 months ago. As shown in the graph 500, Rule B may have an observedpredictive percentage that varies between 60% and 70% over the time fromwhen testing began to 6 months ago. As such, the observed predictivepercentage of Rule B has less variation over time compared to theobserved predictive percentage of Rule A. The larger variation in theobserved percentage for Rule A may indicate that Rule A is sensitive tochanges in user behavior, thereby making Rule A less accurate duringcertain periods of time.

As further described below, the access rule generation system maydetermine a detection stability rating for an access rule based ontrends in the variation of the observed predictive percentages overtime. For example, the rule generation computer may segment the accessrequests of the training set into time-based subsets based on the timingof when the access requests were received. Each segment may correspondto a certain time-period (e.g., time window). The rule generationcomputer may then determine the triggering percentages for each of thetime-based segments and compute the variation of the triggeringpercentages. In some embodiments, the access request may be segmentedweek-by-week or day-by-day. In other embodiments, the access requestsmay be segmented using a sliding window such that the triggeringpercentages are calculated each day over a one week window.

Based on trends in the variation of the predictive percentages for thesegments, the access rule generation system may determine that Rule Bhas a higher detection stability rating compared to Rule A, since theobserved predictive percentage of Rule B varies less over time. Theaccess rule generation system may use the detection stability ratings ofthe potential access rules to select candidate access rules that arestable, and thus, more accurate and more consistent over time.

C. System for Generating and Selecting Access Rules that are Stable OverTime

FIG. 6 shows a functional block diagram of an access rule generationsystem 600 for generating and selecting access rules that are stableover time, in accordance with some embodiments. The access rulegeneration system 600 may determine the variation of the triggeringpercentage and the predictive percentage and select candidate accessrules having higher stability ratings.

The access rule generation system 600 may operate similar to the accessrule generation system 130 of FIG. 1 and the access rule generationsystem 300 of FIG. 3. The access rule generation system 300 may beimplemented in a resource access system similar to the resource accesssystem 100 of FIG. 1 described above.

The access rule generation system 600 may store access requestinformation 610 and corresponding validity information 620 for use ingenerating candidate access rules 624. The access request information610 and the validity information 620 may be received from a resourcecomputer, a request computer, or an access server. At 601, the accessrule generation system 600 may select a subset of access requests fromthe stored access request information 610 to obtain a training set 630of access requests for use in generating the candidate access rules 624.The access rule generation system 600 may select access requests to beincluded in the training set 630 based on the time and date when theaccess request was received. The access rule generation system 600 mayalso select the training set such that it includes both recent accessrequests (e.g., those occurring within the past eighteen months) andhistorical access requests (e.g., those occurring more than eighteenmonths ago).

At 602, the access rule generation system 600 may generate a pluralityof potential access rules 640 based on the training set 630 of accessrequests. In some embodiments, the access rule generation system 600 maygenerate the potential access rules based on a decision tree. Forinstance, each node of the decision tree may represent a condition of anaccess rule parameter and branches of the decision tree may representpotential access rules 640.

After generating the plurality of potential access rules 640, the accessrule generation system 600 may determine, at 603, the performance ofeach of the potential access rule 640. The performance of a potentialaccess rule may be based on the validity information 620 correspondingto the access requests of the training set 630 that satisfy theconditions of the potential access rule. For example, access rulegeneration system 600 may determine a “total predictive percentage” foreach of the potential access rules 940 based on all of the accessrequests in the training set 630 triggering that rule.

At 604, the access rule generation system 600 may determine thetriggering stability and the detection stability of the potential accessrules 640. The access rule generation system 600 may segment the accessrequests of the training set 630 into subsets according to differenttime periods (e.g., week by week, or month by month). In someembodiments, the segments may be based on a sliding window (e.g., a oneweek period calculated for each day). The access rule generation system600 may determine a triggering percentages for each of the plurality oftime-based subsets of access requests. The access rule generation system600 may determine a triggering stability rating by comparing theplurality of triggering percentages. For example, the access rulegeneration system 600 may determine the triggering stability rating ofan access rule based on the variation of the triggering percentages forthe subsets.

The access rule generation system 600 may also determine predictivepercentages for each of the plurality of time-based subsets of accessrequests. The access rule generation system 600 may determine adetection stability rating by comparing the plurality of predictivepercentages. For example, the access rule generation system 600 maydetermine the detection stability rating of an access rule based on thevariation of the predictive percentages for the subsets. The access rulegeneration system 600 may assign higher triggering and detectionstability ratings to the access rules having less triggering variationand less detection variation compared to other potential access rules.

In some circumstances, the predictive percentage of an access rule mayhave a large variation due to its predictive percentage increasing overtime. In this case, the access rule generation server may 600 maydetermine a higher detection stability rating for the access rule.

At 605, the access rule generation system 600 may select a set ofcandidate access rules 634 from the potential access rules 640 bycomparing the performance and the stability ratings of the potentialaccess rues 640. For instance, a more stable access rule may be selectedover a higher performing access rule. The candidate access rules 634 maybe provided to the operator of the resource and some or all of thecandidate access rules 634 made be used as the access rules implementedby an access server.

In addition, the access rule generation system 600 may identifypotential access rules having high performance but low stability. Theaccess rule generation system 600 may add certain conditions to theaccess rule to account for the variability over time, thereby improvingthe access rules performance and stability. As such, the access rulegeneration system 600 may select candidate access rules that are bothhigh performing and consistent in their performance.

III. Delay in Reporting Fraudulent Access Requests

There is typically a delay between the occurrence of fraudulent accessand the reporting of the fraudulent access. The delay may occur becauseauthorized users of the resource may not immediately notice the effectsof the unauthorized access. As such, the validity information for recentaccess requests may be inaccurate until a sufficient amount of time haspassed for occurrences of fraudulent access to be reported. For thisreason, prior access rule generation systems may not include more recentaccess requests in the training set. For example, prior access rulegeneration systems may not consider access requests received within thepast three months or the past six months, for example, due to the delayin reporting. However, not including the most recent access requests inthe training set means that the training set may not be representativeof the most recent patterns of fraudulent activity. As such, accessrules selected based older access requests may not accurately identifyfraudulent access requests made according to new patterns of fraud andthey may also generate more false positives.

To improve the performance of the access rules, the access rulegeneration system may track reports of fraudulent access over time todevelop a reporting time distribution indicating the proportion offraudulent access that has been reported after a certain amount of time.The access rule generation system may compensate the validityinformation corresponding to access requests that trigger a certain rulebased on reports received for other access rules that also trigger thesame rule. The validity information may be compensated according to theexpected reporting delay such that more recent access requests arecompensated more than older access requests. Accordingly, the mostrecently received access requests may be included in the training set,thereby making the candidate access rules more accurate with respect tonew patterns of fraud.

A. Distribution of Reporting Over Time

FIG. 7 shows an exemplary graph 700 of the time delay in the reportingof fraudulent access requests over time, in accordance with someembodiments. The graph 700 shows the percentage of fraudulent accessrequests (e.g., fraudulent access requests that were not rejected) thathave been reported within a certain number of days since the occurrenceof the access request. The x-axis indicates the number of days betweenthe access request being made and the reporting of the access requestbeing fraudulent (e.g., the reporting delay). The y-axis indicates thepercentage of invalid access requests reported within the number of daysindicated on the x-axis. In the example shown in FIG. 7, only a smallpercentage of fraudulent access requests are reported within the firstweek after the fraudulent access occurs. However, after 216 days, 100%of fraudulent access requests that will be reported have been reported.That is, the validity information is 100% accurate after 216 days.

The reporting-delay information may also be represented as shown inTable 1:

TABLE 1 Cumulative Distribution in the Reporting of Fraudulent AccessRequests The reporting-delay information may also be based amathematical function or algorithm that determines a plurality ofreporting percentages for a corresponding plurality of time periods. Atable of reporting-delay information may be based on such a function oralgorithm. Cumulative Percentages 10% 20% 30% 40% 50% 60% 70% 80% 90%95% 100% Reporting 14 24 33 42 52 64 79 98 126 150 216 Delay (days)

Access servers used for different purposes may have different reportingdelays. In addition, different reporting channels may also havedifferent reporting delays. For example, there may be a differentdistribution is the delay time between reports received from users andreports received from resource operators. Accordingly, the reportinginformation used by the access rule generation server may includeseveral different reporting-delay distributions for different type ofaccess requests or different reporting channels. The reporting-delayinformation may be obtained by tracking the time and date that accessrequests were made, the time and date that the access requests werereported as being invalid, and the channel that the report was receivedfrom.

Such reporting-delay distributions may be used to estimate or determinethe total number of invalid access requests that will be reported basedon the number of fraudulent access requests that have already beenreported and the percentage of fraudulent access requests that areexpected to have been reported after a certain delay. As furtherdescribed below, an access rule generation computer may compensaterecently received access requests based on the reporting distribution toaccount for the reporting delay.

B. Compensation of the Observed Fraud Detection Based on the ReportingDelay

FIG. 8 shows a graph 800 of observed predictive percentages andcompensated predictive percentages for an access rule over time, inaccordance with some embodiments. The observed predictive percentage maybe determined based on the percentage of triggering access requests thatwere reported to be fraudulent. However, as discussed above, there maybe a delay in reporting fraudulent access to a resource. Accordingly, asshown in the graph 800, the observed predictive percentage for an accessrule may be lower for more recent time periods (e.g., from six monthsago to today). For example, as shown in the graph 800, the observedpredictive percentage (indicated by the solid line) for a first accessrule, Rule A, may decrease from over 60% prior to 6 months ago to lessthan 1% by today.

However, as described above, a rule generation computer may compensatethe validity information based on reporting-delay information. Thus, thepredictive percentages may be adjusted accordingly, as shown by thedashed line in FIG. 8. The rule generation computer may use thecompensated validity information in determining the stability of theobserved predictive percentage for an access rule. As further describedbelow, the access rule generation system may determine a detectionstability rating for an access rule based on the compensated predictivepercentages.

C. System for Generating and Selecting Access Rules Based on theReporting Delay

FIG. 9 shows a functional block diagram of an access rule generationsystem 900 for generating and selecting access rules based onreporting-delay information, in accordance with some embodiments. Thereporting-delay information may be used to compensate validityinformation, thereby adjusting the predictive percentages and thedetection stability of the access rules. Accordingly, the candidateaccess rules may be more accurate for recent patterns of fraud.

The access rule generation system 900 may operate similar to the accessrule generation system 600 of FIG. 6. The access rule generation system900 may be used in a resource access system similar to the resourceaccess system 100 of FIG. 1 described above.

The access rule generation system 900 may store access requestinformation 910 and corresponding validity information 920 for use ingenerating candidate access rules 934. The access rule generation system900 may also store evaluation information 950 for determining theperformance of access rules that are currently implemented by the accessserver. The evaluation information 950 may include identifiers of theaccess rules that are currently implemented by an access server. Theevaluation information 950 may also include evaluation records includingidentifiers and parameters of the access requests that were allowedduring evaluation of an access rule and identifiers of the evaluatedaccess rules.

The access rule generation system 900 may also store reporting-delayinformation 960 for compensating the validity information. Thereporting-delay information 960 may indicate compensation factors foradjusting the validity information corresponding to recently receivedaccess requests. The compensation factors may be based on the percentageof fraudulent access requests expected to be reported after a certainamount of time. In some embodiments, the reporting-delay information 960may include a function for determining the compensation factor based onbased on the number of days since the access request was accepted. Insome embodiments, the reporting-delay information 960 may include acompensation table indicating compensation factors corresponding to theamount of time since the access request was accepted. The table mayidentify a cumulative percentage of reports expected to be receivedafter a certain number of days similar to Table 1 above. For example,the reporting-delay information 960 may indicate that 10% of reports areexpected to be received within 14 days. Accordingly, the compensationtable may indicate a compensation factor of 10 (e.g., 1÷10%). The accessrequest information 910, the validity information 920, the evaluationinformation, and the reporting-delay information may be received from aresource computer, a request computer, or an access server.

At 901, the access rule generation system 900 may select a subset ofaccess requests from the stored access request information 910 to obtaina training set 930 of access requests for use in generating thecandidate access rules 924. The access rule generation system 900 mayselect access requests to be included in the training set 930 based onthe time and date when the access request was received. The access rulegeneration system 900 may also select the training set such that itincludes both recent access requests (e.g., those occurring within thepast eighteen months) and historical access requests (e.g., thoseoccurring more than eighteen months ago).

At 902, the access rule generation system 900 may generate a pluralityof potential access rules 940 based on the training set 930 of accessrequests. In some embodiments, the access rule generation system 900 maygenerate the potential access rules based on a decision tree. Forinstance, each node of the decision tree may represent a condition of anaccess rule parameter and branches of the decision tree may representpotential access rules 940.

Before determining the performance of the potential access rules, theaccess rule generation system 900 may adjust the validity information920 based on the evaluation information 950 and the reporting-delayinformation 960. At 903, the access rule generation system 900 mayadjust the validity information 920 to account for false positives inthe access requests rejected by the access rules implemented by theaccess server. The validity information 920 may be adjusted to accountfor false positives (e.g., legitimate access requests being denied).

The access rule generation system 900 determine a false positivepercentage for each of the access rules currently implemented by theaccess server based on the validity information 920 and the evaluationinformation 950. As described above with reference to FIG. 2, certainaccess requests may be accepted instead of being rejected in order toevaluate the performance of the access rules that would have rejectedthe access request. For example, the access server may have accepted(instead of rejected) 100 access requests triggered by an access rule(e.g., for evaluation of the access rule) and 60 of those accessrequests may have been reported as being fraudulent. In this example,the outcome of that access rule is a false positive 40% of the time (40out of 100). In some embodiments, the access rule generation system 900may receive such false positive information from the access server, theresource computer, or the request computer.

The access rule generation system 900 may use the false positivepercentage for a currently implemented access rule to weight thevalidity information corresponding to the access requests that triggerthat access rule. For example, a valid access request may be assigned avalidity score of 0.0 and a fraudulent access request may be assigned avalidity score of 1.0 in the validity information 920. The access rulegeneration system 900 may adjust the validity scores for the rejectedaccess requests (e.g., the requests that were not allowed for evaluationof the access rule) to account for the false positive percentage.Accordingly, the validity score of the rejected access requests may beadjusted from 1.0 to 0.6 based on the false positive percentage of 40%.Accordingly, the validity information 920 for the rejected accessrequests may account for the evaluation information indicating that theaccess rule generates false positives 40% of the time.

The adjusted validity information 920 (e.g., validity score) may be usedby the access rule generation system 900 in determining the performanceof the potential access rules 940. Therefore, the access rule generationsystem 900 may determine a fraud predictive percentage for potentialaccess rules having the same, or similar, conditions as the currentlyimplemented access rules. Therefore, the access rule generation system900 provides improved candidate rule selection since it may update orreplace certain underperforming access rules that are currently beingimplemented by the access server. As such, the access rules generationsystem 900 overcomes the problems of prior rule generation systems whichare not able to evaluate the performance of the currently implementedrules.

Having fewer false positives is advantageous to users and user device.Depending on the purpose and implementation of the access server, higherperforming (e.g., less false positives) access rules selected by theaccess rule generation system 900 may lead to fewer users being deniedaccess to their website accounts, fewer legitimate transactions forgoods or services being denied, and fewer legitimate emails beinglabeled as “junk” email. In addition, user devices may consume fewernetwork resources since legitimate access requests will not need to bere-sent as often since the access rules produce fewer false positives.

The access rule generation computer may further adjust the validityinformation. At 904, the access rule generation system 900 maycompensate the validity information 920 to account for the reportingdelay based on the reporting-delay information 960. The reporting-delayinformation 960 may indicate compensation factors for compensatingrecently received access requests. The compensation factors may be basedon the percentage of fraudulent access requests expected to be reportedafter a certain amount of time since the access request was accepted. Insome embodiments, the reporting-delay information 960 may include afunction or a table for determining the compensation factor based onbased on the number of days since the access request was accepted.

In one example of compensating validity information, the reporting-delayinformation 960 may indicate that 30% of reports are expected to bereceived within 33 days and that 40% of reports are expected to bereceived within 42 days of the access request being made. Accordingly,the reporting-delay information 960 may indicate a compensation factorof 2.5 (e.g., 100%÷40%) for access requests received within the past 34to 42 days. In this example, the access rule generation system 900compensate the reported access requests that were received within thepast 34 to 42 days based on the compensation factor of 2.5. Accordingly,if a fraudulent access request is assigned a validity score of 1.0, thenthe compensated validity score would be 2.5. The access rule generationsystem 900 may compensate each the access requests according to thereporting-delay information 960.

After generating the plurality of potential access rules 940, the accessrule generation system 900 may determine, at 905, the performance ofeach of the potential access rule 940. The performance of a potentialaccess rule may be based on the validity information 920 correspondingto the access requests of the training set 930 that satisfy theconditions of the potential access rule. As discussed above, thevalidity information 920 may be adjusted to account for false positivesand it may be compensated to account for the reporting delay. The accessrule generation system 900 may determine the performance of a potentialaccess rule 940 based on its predictive percentage.

After determining the performance of the potential access rules 940, theaccess rule generation system 900 may determine, at 906, the triggeringstability and the detection stability of the potential access rules 940.The access rule generation system 900 may segment the access requests ofthe training set 930 into different time periods (e.g., week by week, ormonth by month). In some embodiments, the segments may be based on asliding window (e.g., a one week period calculated for each day). Theaccess rule generation system 900 may determine the triggering variationof an access rule based on the variation of its triggering percentagesfor each of the segments. The access rule generation system 900 may alsodetermine the detection variation of an access rule based on thevariation of its predictive percentages for each of the segments. Theaccess rule generation system 900 may assign higher stability ratings tothe access rules having less triggering variation and less detectionvariation.

After determining the performance and the stability of the potentialaccess rules 940, the access rule generation system 900 may select, at907, a set of candidate access rules 934, from the potential accessrules 940 by comparing the performance and the stability ratings of thepotential access rues 940. For instance, a more stable access rule maybe selected over a higher performing access rule. The candidate accessrules 934 may be provided to the operator of the resource and some orall of the candidate access rules 934 made be used as the access rulesimplemented by an access server.

Accordingly, the candidate access rules 934 generated and selected bythe access rule generation system 900 may have a higher predictivepercentage and produce fewer false positives since the rule generationprocess adjusted the validation information based on the evaluationinformation and the reporting-delay information and because thecandidate access rule selection considered the stability of thepotential access rules over time.

Furthermore, after generating and selecting the candidate access rules934, the access rule generation system 900 may periodically receive oneor more of: updated access request information 910, updated validityinformation 920, updated evaluation information 950, and updatedreporting information 960. In response to receiving updated information,the access rule generation system 900 may generate and select a new setof candidate access rules using updated information according to theprocess described above. The access rule generation system 900 may thenprovide a new or updated set of candidate access rules to the accessserver. As such, the access rules implemented by the access server maybe responsive to the most recent patterns of fraud, thereby reducingfraudulent access and also reducing false positives.

IV. Exemplary Methods for Access Rule Generation

A. Exemplary Method for Generating and Selecting Stable Access Rules

FIG. 10 shows a flowchart 1000 of a method for generating and selectingstable access rules, in accordance with some embodiments. The method maybe performed by a computer system, such as the resource security systemdescribed herein. In some embodiments, some of the method steps may notbe performed or the steps may be performed in a different order.

At step 1001, the computer system may store a plurality of previousaccess requests and parameters of the plurality of previous accessrequests. The plurality of previous access requests and parameters ofthe plurality of previous access requests may be used to generatecandidate access rules. In some embodiments, the computer system mayreduce the plurality of previous access requests to a training subset ofaccess requests. For example, an access rule generation system may storeaccess request information and select a training set of access requestas discussed above.

At step 1002, the computer system may store validity informationcorresponding to the plurality of previous access requests. The validityinformation may indicate whether an access request is fraudulent,legitimate, or declined (e.g., rejected based on the access rules). Thevalidation information may include validity scores corresponding to eachaccess request of the plurality of previous access requests. Thevalidity information may be based on reports of fraudulent access. Forexample, an access rule generation system may store validity informationas discussed above.

At step 1003, the computer system may generate a potential access ruleincluding one or more conditions. The potential access rules may betriggered by access requests involving the one or more conditions of theaccess rule. The potential access rule may provide an access ruleoutcome (e.g., accept, reject, or review) when it is triggered. In someembodiments, the computer system may generate the potential access rulebased on a decision tree where each node of the decision tree representsa condition and the branches of the decision tree represent potentialaccess rules. For example, an access rule generation system maypotential access rules based on the training set of access requests asdiscussed above.

At step 1004, the computer system may determine a first set of previousaccess requests of the plurality of previous access requests. The firstset of previous access requests may involve the one or more conditionsof the potential access rule. That is, the first set of previous accessrequests may trigger the potential access rule. For example, prior todetermining the performance of a potential access rule, an access rulegeneration system may determine which access requests of a training setof access requests trigger the potential access rule.

At step 1005, the computer system may determine a total predictivepercentage for the first access rule based on the validity information.The total predictive percentage may be based on the percentage of accessrequest triggering the potential access rule that are fraudulent basedon the validity information. For example, an access rule generationsystem may determine the performance of a potential access rule based onthe validity information corresponding to the access request of thetraining set that trigger that access rule.

At step 1006, the computer system may segment the first set of previousaccess requests into a plurality of time-based subsets of accessrequests. Each segment may correspond to a certain time-period (e.g.,time window). In some embodiments, the access request may be segmentedweek-by-week or day-by-day. In other embodiments, the access requestsmay be segmented using a sliding window such that the triggeringpercentages are calculated each day over a one week window. For example,an access rule generation system may determine the triggering stabilityand the detection stability of an access rule by segmenting the accessrequests of a training set of access requests into a plurality ofsubsets based on the timing of when the access requests were received.

At step 1007, the computer system may determine a predictive percentagefor each of the plurality of time-based subsets. The predictivepercentages may be based on the validity information corresponding toeach of the access requests in the subsets. For example, an access rulegeneration system may determine the triggering percentage and thepredictive percentage of an access rule during certain periods of time(e.g., time windows) based on the access request information and thevalidity information.

At step 1008, the computer system may determine a detection stabilityrating of the first access rule by comparing the plurality of predictivepercentages. The detection stability rating of the first access rule maybe based on a computed variation of the predictive percentages such thedetection stability rating increases as the variation decreases. Forexample, an access rule generation system may determine a detectionstability rating based by computing the variation of the detectionstability across each of the subsets, which correspond to different timeperiods.

At step 1009, the computer system may select the potential access ruleto be included in an operational set of access rules based on thedetection stability rating. The selection of the potential access ruleto be included in the operational set may also be based on the totalpredictive percentage of the access rule. The selection may also bebased on a comparison of the detection stability rating compared tostability ratings of other potential access rules. For example, anaccess rule generation system may select a set of candidate access rulesfrom set of the potential access rules as discussed above.

At step 1010, the computer system may load the operational set of accessrules into a system memory. The system memory may comprise RAM, ROM,EEPROM, or flash memory, for example. The system memory may containcode, for implementing the methods described herein. The system memorymay be load data from a computer-readable storage medium, such as a harddisk drive or a solid state drive. The system memory may also load datafrom network-accessible storage media, such as from a database server.For example, an access server may load the access rules received fromthe access rule generation system into a system memory of the accessserver.

At step 1011, the computer system may receive, from a plurality ofdevices, a plurality of real-time access requests. For example, theaccess server may receive a plurality of real-time access requests froma user device or an access device, via a resource computer, as discussedabove. The access requests may include parameters for each of the accessrequests.

At step 1012, when one of the access requests are received, the computersystem may obtain the operational set of access rules from the systemmemory. For example, when an access server receives an access requestfrom a resource computer, the access server may obtain the access rulesfrom the system memory.

At step 1013, the computer system may use the operational set of accessrules to determine an access request outcome for one of the real-timeaccess requests. The access request outcome may be based on a pluralityof access request outcomes provided by the operational set of accessrules based on the parameters of the access request. The access requestoutcome may indicate to accept, reject, or review the access request.For example, an access server may determine an access request outcomebased on the access rules as described above.

At step 1014, the computer system may provide access to the resourcebased on the access request outcome. For example, the computer systemmay provide access to the resource if the access request outcomeindicates to accept the access request. The computer system may notprovide access to the resource if the access request outcome indicatedto reject the access request. For example, as discussed above, an accessserver may send an indication to a resource computer for the accessrequest to be accepted and then the resource computer may provide accessto the resource.

B. Exemplary Method for Generating and Selecting Access Rules Based onCompensated Validity Information

FIG. 11 shows a flowchart 1100 of a method for generating and selectingaccess rules based on compensated validity information, in accordancewith some embodiments. The method may be performed by a computer system,such as the resource security system described herein. In someembodiments, some of the method steps may not be performed or the stepsmay be performed in a different order.

At step 1101, the computer system may store a plurality of previousaccess requests and parameters of the plurality of previous accessrequests. The plurality of previous access requests and parameters ofthe plurality of previous access requests may be used to generatecandidate access rules. In some embodiments, the computer system mayreduce the plurality of previous access requests to a training subset ofaccess requests. For example, an access rule generation system may storeaccess request information and select a training set of access requestas discussed above.

At step 1102, the computer system may store validity informationcorresponding to the plurality of previous access requests. The validityinformation may indicate whether an access request is fraudulent orlegitimate. The validation information may include validity scorescorresponding to each access request of the plurality of previous accessrequests. The validity information may be based on reports of fraudulentaccess. For example, an access rule generation system may store validityinformation as discussed above.

At step 1103, the computer system may compensate the validityinformation based on reporting-delay information. The computer systemmay compensate the validity information based on a reporting-delaydistribution indicating an expected amount of time between the time whenthe access request was made and the time when fraudulent access wasreported. For example, a validity score for an access request may becompensated based on compensation factors determined using thereporting-delay information. For example, an access rule generationsystem may compensate validity information using compensation factorsthat are based on reporting-delay information.

At step 1104, the computer system may generate a potential access ruleincluding one or more conditions. The potential access rules may betriggered by access requests involving the one or more conditions of theaccess rule. The access rule may provide an access rule outcome (e.g.,accept, reject, or review) when it is triggered. In some embodiments,the computer system may generate the potential access rules based on adecision tree where each node of the decision tree represents acondition of an access rule parameter and the branches of the decisiontree represent the potential access rules. For example, an access rulegeneration system may potential access rules based on the training setof access requests as discussed above.

At step 1105, the computer system may determine a first set of previousaccess requests of the plurality of previous access requests. The firstset of previous access requests may involve the one or more conditionsof the potential access rule. That is, the first set of previous accessrequests may trigger the potential access rule. For example, prior todetermining the performance of a potential access rule, an access rulegeneration system may determine which access requests of a training setof access requests trigger the potential access rule.

At step 1106, the computer system may determine a total predictivepercentage for the first access rule based on the compensated validityinformation corresponding to the first set. The total predictivepercentage may be based on the percentage of access request triggeringthe potential access rule that are fraudulent based on the validityinformation. For example, an access rule generation system may determinethe performance of a potential access rule based on the validityinformation corresponding to the access request of the training set thattrigger that access rule.

At step 1107, the computer system may select the first access rule to beincluded in an operational set of access rules based on the totalpredictive percentage. The selection of the potential access rule to beincluded in the operational set may also be based on the totalpredictive percentage of the access rule. The selection may also bebased on a comparison of the detection stability rating compared tostability ratings of other potential access rules. For example, anaccess rule generation system may select a set of candidate access rulesfrom set of the potential access rules as discussed above.

At step 1108, the computer system may load the operational set of accessrules into a system memory. The system memory may comprise RAM, ROM,EEPROM, or flash memory, for example. The system memory may containcode, for implementing the methods described herein. The system memorymay be load data from a computer-readable storage medium, such as a harddisk drive or a solid state drive. The system memory may also load datafrom network-accessible storage media, such as from a database server.For example, an access server may load the access rules received fromthe access rule generation system into a system memory of the accessserver.

At step 1109, the computer system may receive, from a plurality ofdevices, a plurality of real-time access requests. For example, theaccess server may receive a plurality of real-time access requests froma user device or an access device, via a resource computer, as discussedabove. The access requests may include parameters for each of the accessrequests.

At step 1110, when one of the access requests are received, the computersystem may obtain the operational set of access rules from the systemmemory. For example, when an access server receives an access requestfrom a resource computer, the access server may obtain the access rulesfrom the system memory.

At step 1111, the computer system may use the operational set of accessrules to determine an access request outcome for one of the real-timeaccess requests. The access request outcome may be based on a pluralityof access request outcomes provided by the operational set of accessrules based on the parameters of the access request. The access requestoutcome may indicate to accept, reject, or review the access request.For example, an access server may determine an access request outcomebased on the access rules as described above.

At step 1112, the computer system may provide access to the resourcebased on the access request outcome. For example, the computer systemmay provide access to the resource if the access request outcomeindicates to accept the access request. The computer system may notprovide access to the resource if the access request outcome indicatedto reject the access request. For example, as discussed above, an accessserver may send an indication to a resource computer for the accessrequest to be accepted and then the resource computer may provide accessto the resource.

V. Exemplary Computer Systems for Access Rule Generation andImplementation

The embodiments described above may involve implementing one or morefunctions, processes, operations or method steps. In some embodiments,the functions, processes, operations or method steps may be implementedas a result of the execution of a set of instructions or software codeby a suitably-programmed computing device, microprocessor, dataprocessor, or the like. The set of instructions or software code may bestored in a memory or other form of data storage element which isaccessed by the computing device, microprocessor, etc. In otherembodiments, the functions, processes, operations or method steps may beimplemented by firmware or a dedicated processor, integrated circuit,etc.

FIG. 12 shows a functional block diagram 1200 of components of anexemplary computer system including an access rule generation system1230 and an access server 1220, in accordance with some embodiments. Thevarious components may be embodied by computer hardware or computer codestored on a non-transitory computer readable storage medium.

The access rule generation system 1230 may comprise one or moreprocessor circuits 1231. The processor circuits 1231 may executeinstructions to perform the functions of the access rule generationsystems described herein (e.g., generating and selecting access rules).The processor circuits 1231 may be coupled to one or more memory units1232 that are configured to store data and instructions. The memoryunits 1232 may be non-transitory computer-readable storage medium. Theprocessor circuits 1231 may read data from the memory units 1232 andwrite data to the memory units 1232. For example, the processor circuits1231 may load into the memory units 1232 a plurality of access requestinformation, validity information, reporting-delay information,evaluation information, training set data, information related accessrule performance, and information related to access rule generation, andinformation related to access rule selection as described herein.

The access rule generation system 1230 may also comprise a communicationinterface 1233. The communication interface 1233 may receivecommunications from a communication interface of another computer, suchas communications from a resource computer or an access server. Thecommunication interface 1233 may also transmit communications to anothercomputer. As described herein, the access rule generation system 1230may receive access request information, reporting information,evaluation information, and reporting information from a resourcecomputer or an access server.

The access rule generation system 1230 may also comprise one or morestorage drives 1234. The storage drives 1234 may be directly coupled tothe access rule generation system 1230 or they may be network accessstorage drives 1234. The storage drives 1234 may comprise one or moredatabases for storing the access request information, the reportinginformation, the evaluation information, and the reporting informationdescribed herein. The storage drives 1234 may store data that may beloaded into the memory units 1232 by the processor circuits 1231.

The access server 1220 may comprise one or more processor circuits 1221.The processor circuits 1221 may execute instructions to perform thefunctions of the access servers described herein (e.g., operating accessrules to accept, reject, or review access requests). The processorcircuits 1221 may be coupled to one or more memory units 1222 that areconfigured to store data and instructions. The memory units 1222 may benon-transitory computer-readable storage medium. The processor circuits1221 may read data from the memory units 1222 and write data to thememory units 1222. For example, the processor circuits 1221 may loadinto the memory units 1222 a plurality of access request rules andparameters of an access request in order to determine an access requestoutcome, as described herein.

The access server 1220 may also comprise a communication interface 1223.The communication interface 1223 may receive communications from acommunication interface of another computer, such as communications froma resource computer or an access server. The communication interface1223 of the access server 1220 may communicate with the communicationinterface 1223 of the access rule generation system 1230. Thecommunication interface 1223 may also transmit communications to anothercomputer. The access server 1220 may receive access request informationand access request parameters via the communication interface 1223.

The access server 1220 may also comprise one or more storage drives1224. The storage drives 1224 may be directly coupled to the accessserver 1220 or they may be network accessible storage drives 1224. Thestorage drives 1224 may comprise one or more databases for storing theaccess request information and the access request parameters. Thestorage drives 1224 may store data that may be loaded into the memoryunits 1232 by the processor circuits 1221.

The above description is illustrative and is not restrictive. Manyvariations of the invention may become apparent to those skilled in theart upon review of the disclosure. The scope of the invention may,therefore, be determined not with reference to the above description,but instead may be determined with reference to the pending claims alongwith their full scope or equivalents.

It should be understood that any of the embodiments of the presentinvention can be implemented in the form of control logic using hardware(e.g. an application specific integrated circuit or field programmablegate array) and/or using computer software with a generally programmableprocessor in a modular or integrated manner. As used herein, a processorincludes a single-core processor, multi-core processor on a sameintegrated chip, or multiple processing units on a single circuit boardor networked. Based on the disclosure and teachings provided herein, aperson of ordinary skill in the art will know and appreciate other waysand/or methods to implement embodiments of the present invention usinghardware and a combination of hardware and software.

Any of the software components or functions described in thisapplication may be implemented as software code to be executed by aprocessor using any suitable computer language such as, for example,Java, C, C++, C#, Objective-C, Swift, or scripting language such as Perlor Python using, for example, conventional or object-orientedtechniques. The software code may be stored as a series of instructionsor commands on a computer readable medium for storage and/ortransmission. A suitable non-transitory computer readable medium caninclude random access memory (RAM), a read only memory (ROM), a magneticmedium such as a hard-drive or a floppy disk, or an optical medium suchas a compact disk (CD) or DVD (digital versatile disk), flash memory,and the like. The computer readable medium may be any combination ofsuch storage or transmission devices.

Storage media and computer-readable media for containing code, orportions of code, can include any appropriate media known or used in theart, including storage media and communication media, such as but notlimited to volatile and non-volatile, removable and non-removable mediaimplemented in any method or technology for storage and/or transmissionof information such as computer-readable instructions, data structures,program modules, or other data, including RAM, ROM, EEPROM, flash memoryor other memory technology, CD-ROM, digital versatile disk (DVD) orother optical storage, magnetic cassettes, magnetic tape, magnetic diskstorage or other magnetic storage devices, data signals, datatransmissions, or any other medium which can be used to store ortransmit the desired information and which can be accessed by thecomputer. Based on the disclosure and teachings provided herein, aperson of ordinary skill in the art will appreciate other ways and/ormethods to implement the various embodiments.

Such programs may also be encoded and transmitted using carrier signalsadapted for transmission via wired, optical, and/or wireless networksconforming to a variety of protocols, including the Internet. As such, acomputer readable medium according to an embodiment of the presentinvention may be created using a data signal encoded with such programs.Computer readable media encoded with the program code may be packagedwith a compatible device or provided separately from other devices(e.g., via Internet download). Any such computer readable medium mayreside on or within a single computer product (e.g. a hard drive, a CD,or an entire computer system), and may be present on or within differentcomputer products within a system or network. A computer system mayinclude a monitor, printer, or other suitable display for providing anyof the results mentioned herein to a user.

Any of the methods described herein may be totally or partiallyperformed with a computer system including one or more processors, whichcan be configured to perform the steps. Thus, embodiments can bedirected to computer systems configured to perform the steps of any ofthe methods described herein, potentially with different componentsperforming a respective steps or a respective group of steps. Althoughpresented as numbered steps, steps of methods herein can be performed ata same time or in a different order. Additionally, portions of thesesteps may be used with portions of other steps from other methods. Also,all or portions of a step may be optional. Additionally, any of thesteps of any of the methods can be performed with modules, units,circuits, or other means for performing these steps.

The specific details of particular embodiments may be combined in anysuitable manner without departing from the spirit and scope ofembodiments of the invention. However, other embodiments of theinvention may be directed to specific embodiments relating to eachindividual aspect, or specific combinations of these individual aspects.

The above description of example embodiments of the invention has beenpresented for the purposes of illustration and description. It is notintended to be exhaustive or to limit the invention to the precise formdescribed, and many modifications and variations are possible in lightof the teaching above.

A recitation of “a”, “an” or “the” is intended to mean “one or more”unless specifically indicated to the contrary. The use of “or” isintended to mean an “inclusive or,” and not an “exclusive or” unlessspecifically indicated to the contrary.

All patents, patent applications, publications, and descriptionsmentioned herein are incorporated by reference in their entirety for allpurposes. None is admitted to be prior art.

What is claimed is:
 1. A method for securing access to a resource, themethod comprising performing, by a computer system: storing validityinformation corresponding to a plurality of previous access requests,the validity information indicating whether each access request of theplurality of previous access requests is valid or invalid; compensatingthe validity information based on a reporting-delay distributionindicating percentages of access requests that are expected to have beenreported as valid or invalid over time relative to when the accessrequests were received; determining a first set of previous accessrequests from the plurality of previous access requests, each previousaccess request of the first set including one or more parameters thatinvolve one or more conditions of a potential access rule; determining atotal predictive percentage for the potential access rule based on thecompensated validity information corresponding to each previous accessrequest of the first set of previous access requests; and selecting thepotential access rule to be included in an operational set of accessrules based on the total predictive percentage, wherein the operationalset of access rules is loaded into a system memory, and the operationalset of access rules is used to determine an access request outcome for areal-time access request for the resource.
 2. The method of claim 1,wherein the validity information corresponding to a recent accessrequest is compensated more than the validity information correspondingto a later access request.
 3. The method of claim 1, further comprising:determining a stability rating of the potential access rule based on thecompensated validity information, wherein the selection of the potentialaccess rule to be included in the operational set of access rules isfurther based on the stability rating of the potential access rulecompared to stability ratings of other access rules.
 4. The method ofclaim 1, further comprising: including the potential access rule in theoperational set of access rules based on the total predictive percentageof the potential access rule compared to a total predictive percentageof other access rules; loading the operational set of access rules intothe system memory; receiving, over a network from a plurality ofdevices, a plurality of real-time access requests; accessing the systemmemory to obtain the operational set of access rules when one of theplurality of real-time access requests is received from a first deviceof the plurality of devices; using the operational set of access rulesto determine the access request outcome for the real-time accessrequest; and providing access to the resource based on the accessrequest outcome.
 5. The method of claim 1, wherein the reporting-delaydistribution includes a plurality of time periods and a correspondingplurality of reporting percentages, the corresponding plurality ofreporting percentages indicating the percentages of access requests thatare expected to have been reported within the plurality of time periodsrelative to when an access request is received.
 6. The method of claim1, wherein the reporting-delay distribution is obtained by tracking afirst time that each access request of the plurality of previous accessrequests was made, a second time that each of a portion of the pluralityof previous access requests was reported as being invalid, and acommunication channel through which a report was received.
 7. The methodof claim 6, wherein the communication channel is one of a plurality ofchannels that includes a user channel and a resource operator channel,and reports for respective channels of the plurality of channels havedifferent reporting-delay distributions.
 8. The method of claim 6,wherein compensating the validity information further comprises:determining, using the reporting-delay distribution of the communicationchannel, a total number of invalid access requests predicted to bereported based on the portion that was reported as being invalid and apercentage of access requests that are expected to be reported asinvalid after a delay.
 9. The method of claim 1, further comprisingadjusting the validity information based on false positive percentagesof the operational set of access rules.
 10. The method of claim 1,wherein selecting the potential access rule further comprises:determining a second total predictive percentage for a currentlyimplemented access rule, wherein one or more conditions of the currentlyimplemented access rule is the same as at least one of the one or moreconditions of the potential access rule; and determining that the totalpredictive percentage for the potential access rule is greater than thesecond total predictive percentage for the currently implemented accessrule.
 11. A computer system, comprising: a computer readable storagemedium storing a plurality of instructions; and one or more processorsfor executing the instructions stored on the computer readable storagemedium to: store validity information corresponding to a plurality ofprevious access requests, the validity information indicating whethereach access request of the plurality of previous access requests isvalid or invalid; compensate the validity information based on areporting-delay distribution indicating percentages of access requeststhat are expected to have been reported as valid or invalid over timerelative to when the access requests were received; determine a firstset of previous access requests from the plurality of previous accessrequests, each previous access request of the first set including one ormore parameters that involve one or more conditions of a potentialaccess rule; determine a total predictive percentage for the potentialaccess rule based on the compensated validity information correspondingto each previous access request of the first set of previous accessrequests; and select the potential access rule to be included in anoperational set of access rules based on the total predictivepercentage, wherein the operational set of access rules is loaded into asystem memory, and the operational set of access rules is used todetermine an access request outcome for a real-time access request for aresource.
 12. The computer system of claim 11, wherein the validityinformation corresponding to a recent access request is compensated morethan the validity information corresponding to a later access request.13. The computer system of claim 11, wherein the reporting-delaydistribution includes a plurality of time periods and a correspondingplurality of reporting percentages, the corresponding plurality ofreporting percentages indicating percentages of access requests that areexpected to have been reported within the plurality of time periodsrelative to when an access request is received.
 14. The computer systemof claim 11, further comprising instructions to: adjust the validityinformation based on false positive percentages of the operational setof access rules.
 15. The computer system of claim 11, further comprisinginstructions to: determine a second total predictive percentage for acurrently implemented access rule, wherein one or more conditions of thecurrently implemented access rule is the same as the one or moreconditions of the potential access rule; and determine that the totalpredictive percentage for the potential access rule is greater than thesecond total predictive percentage for the currently implemented accessrule.
 16. The computer system of claim 11, further comprisinginstructions to: segment the plurality of previous access requests intoa plurality of time-based subsets of access requests, the first setbeing one of the plurality of time-based subsets; determine a pluralityof predictive percentages including a predictive percentage for each ofthe plurality of time-based subsets based on compensated validityinformation corresponding to each previous access request of thetime-based subsets; and determine a detection stability rating of thepotential access rule by comparing the plurality of predictivepercentages, wherein the selecting of the potential access rule to beincluded in the operational set of access rules is further based on thedetection stability rating of the potential access rule compared todetection stability ratings of other access rules.
 17. The computersystem of claim 16, further comprising instructions to: determine adetection variation of the plurality of predictive percentages, whereindetermining the detection stability rating of the potential access ruleis further based on a trend of the detection variation over time. 18.The computer system of claim 16, further comprising instructions to:determine a triggering percentage for each of the plurality oftime-based subsets based on the validity information corresponding toeach previous access request of the time-based subsets; determine atriggering stability rating of the potential access rule by comparingthe triggering percentages, wherein the selecting of the potentialaccess rule to be included in the operational set of access rules isfurther based on the triggering stability rating of the potential accessrule; and determine a triggering variation of the triggeringpercentages, wherein the determining of the detection stability ratingof the potential access rule is further based on the triggeringvariation.
 19. The computer system of claim 11, further comprisinginstructions to: include the potential access rule in the operationalset of access rules based on the total predictive percentage of thepotential access rule compared to a total predictive percentage of otheraccess rules; load the operational set of access rules into the systemmemory; receive, over a network from a plurality of devices, a pluralityof real-time access requests; access the system memory to obtain theoperational set of access rules when one of the plurality of real-timeaccess requests is received from a first device of the plurality ofdevices; use the operational set of access rules to determine the accessrequest outcome for the real-time access request; and provide access tothe resource based on the access request outcome.
 20. The computersystem of claim 11, wherein the plurality of previous access requestsincludes at least one previous access request that was received within apast week and at least one previous access request that was receivedmore than eighteen months ago.